One of the things that changes the children's minds about Atticus is when he shoots Tim Johnson, the rabid dog, in the street. Heck Tate was prepared to do the job himself, but didn't feel he could pull off the shot. He asks Atticus to take it, knowing that Atticus is perhaps the best shot in Maycomb. Atticus also sheds his glasses in order to take the shot. One might think of Clark Kent taking off his glasses to become Superman in this scene, a very humble Superman.
Atticus pushed his glasses to his forehead; they slipped down, and he dropped them in the street. In the silence, I heard them crack. Atticus rubbed his eyes and chin; we saw him blink hard.
What's interesting here is that Atticus is pressed for time so he doesn't bother to set his glasses down gently. He is simply a man of action. When Atticus takes the dog down with one shot, Scout and especially Jem are amazed. Miss Maudie asks them if they are still ashamed of their father? Scout replies, "Nome." Jem also rightly assumed that Atticus is a gentleman and gentlemen don't brag about their actions. When Scout tells Jem that they'll have something to talk about at school, Jem tells her not to mention it. Jem now looks up to Atticus, not just because he showed some action, but because he wouldn't brag about it:
Atticus is real old, but I wouldn’t care if he couldn’t do anything—I wouldn’t care if he couldn’t do a blessed thing.” Jem picked up a rock and threw it jubilantly at the carhouse. Running after it, he called back: “Atticus is a gentleman, just like me!”